GM Piston Slap

[JKinney]

A family member has piston slap on a 3. 1 ltr engine when cold I did a search and there is a lot of GM engines with piston slap.



I was wondering if amsoil would quiet this down any comments?

 

[fox]

If any oil would reduce the slap. it would be a top end oil like Amsoil.

The cause is too much clearance at the skirt. Sometimes due to a colapsed one. I drove a 427 chevy -30 years ago - that had a skirt collapsed, for two years then sold the car.

Don't worry too much about it.

 

[Vaughn MacKenzie]

A friend has a '01 GMC truck with the 6. 0L and had piston slap. He tried Mobil synthetic and that made it worse. I then suggested Delo 400 and I think he's trying that now, and the problem diminished considerably.



Vaughn

 

[Philip]

Gm has replaced a lot of engines with piston slap in the last few years. If the vehicle is still under warrenty take it in.

 

[JKinney]

The vehicle went in todayit is out of warranty but the noise has been there since inception.



The dealer admits there is a problem and they notified gm which in turn is sending the are rep in to look at the engine.

 

[kentdiesel]

The late model GM gas engine pistons I've seen have a very short,almost non-existent shirt. My first thought upon seeing one of these pistons was: "What a stupid idea. "

It appears to me that the piston to bore clearance would need to be on the mininal end of the spec to prevent piston rock.

 

[lschultz]

Fellow I work with has a 03 chevy truck with the 6. 0 and it has piston slap bad. He just keeps on driving it.

 

[Rosco]

My wifes '03 Tahoe with the 5. 3 slaps away when cold and I have chosen to ignore it.

 

[EMD Diesel Power]

And alot of these have another problem with the piston slap..... yeah, the short skirt aggravates it, but its engine/spark timing as well. GM really screwed up the engineering on these motors and aren't willing to admit it. Also they havent been hitting the tolerances very well during manufacturing either. Basically the plugs are firing before the piston has come up to TDC on compression stroke.



sooo... . its piston slap and detonation too for some of these engines.



Found this out from the guy that just rebuilt the auto transmission in my Dad's 1500. He sees everything from all the Big 3... ... and doesnt BS around either, just gives the cold facts and lets you make a decision.



Jeff

 

[Hale on wheels]

It is not a problem isolated to GM... my wife's Jeep Grand Cherokee with the 4. 7HO sounds the same way, and has since new.

 

[bmoeller]

http://pistonslap.com/